1. Field of the Invention
The present invention relates to an image forming method, and a color filter, a spacer for a liquid crystal display device and a projection for orientation control formed thereby. More specifically, the invention relates to an image forming method used suitably for a liquid crystal display device for both reflection and transmission modes, and a color filter, a spacer for a liquid crystal display device and a projection for orientation control formed thereby.
2. Description of the Related Art
A color filter is used in a color face plate for a cathode-ray tube display, a photoelectric transducer for copying, a filter for a single tube system color television camera, a flat panel display using liquid crystal, a color solid state image sensor, and the like. Color filters are generally composed of regularly-arranged pixels of the three primary colors of blue, green and red. Color filters which include four or more hues are also produced as the need arises.
In recent years, in a field of liquid crystal display device (LCD), a reflection type liquid crystal display device has been developed as a portable terminal, a typical example of which is a portable telephone. However, the reflection type liquid crystal display device has a problem, in that a display quality thereof deteriorates indoors or in dark places. Thus, a liquid crystal display device for both reflection and transmission modes has been considered as an improvement measures.
An example of an embodiment of a structure of the liquid crystal display device for both reflection and transmission modes is illustrated in FIG. 3. In this embodiment, reflecting layers 12, which may be referred to as reflecting plates, are arranged at given intervals on a light transmissible substrate 10B. Transparent layers 16 are arranged at given intervals on a light transmissible substrate 10A. Pixels 14 are formed to cover a part of each of the transparent layers 16. The light transmissible substrate 10A and the light transmissible substrate 10B are arranged to be opposite to each other. Between the substrates is disposed a liquid crystal layer 18.
In the case of transmission display, the display is performed by transmitted light a from a backlight 20. In the case of reflection display, the display is attained by reflected light c resulting from external light b being transmitted through the light transmissible substrate 10A and reflected by the reflecting layer 12.
In this case, the thickness of the light-transmitted portion in the transmission section, though which the light is transmitted, is equal to the thickness of the light-transmitted portion of the reflection section, therefore, in a case in which sufficient brightness is realized in reflection display, the color purity of the transmission section is insufficient. Conversely, in a case in which the color purity of the transmission section is made sufficient, an inconvenience occurs, in which the refection section becomes dark. In order to solve such problems and improve display quality, making the thickness or the hue of the transmission section in a color filter different from that of the reflection section in the color filter has been attempted. However, since the process for producing such a color filter is complicated, costs for production thereof increase.
Further, in order to improve functions of an LCD panel, developments for increasing an angle of visiting or a contrast thereof have been made. As a result of the developments, use of a VA method using a vertical orientation mode and a formation of a photo spacer have been becoming mainstream. The mainstream manner requires a photolithographic step of forming the structure of the spacer and another photolithographic step of forming a projection structure for orientation control, which is essential for the VA method. Therefore, costs for the production of the LCD panel increase.